Northern Airborne Technology 802 - Manual (Page 24)

802-009 Switch Panel
SM802 Installation and Operation Manual
Section 3 Rev: 1.00 Issue 4 Page 3-4
ENG-FORM: 806-0112.DOT
CONFIDENTIAL AND PROPRIETARY TO NORTHERN AIRBORNE TECHNOLOGY LTD.
connected to the microphone input being used. If the MIC SELECT switch is in any of the four transmitter
positions and the SPKR switch is ON, then during a transmit PTT the cockpit speaker volume will be
muted to a preset level determined by the SPKR MUTE adjustment on the Model 700 Amplifier. If the
INPH switch is ON, then the HOT MIC interphone volume will be completely muted during a transmit PTT
as defined in Model 700 software logic.
3.3.6.2 PA Transmission
To key the passenger address amplifier and adjust its volume, the MIC SELECT switch must be placed in
the PASS position. The PA amplifier may then be keyed by either hand mic or yoke PTT key switches
and a passenger address announcement may be made to the cabin. The PASS volume controls the
volume of the PA amplifier output. The cockpit speaker and interphone volumes are not muted during
transmit PTT when the MIC SELECT switch is in the PASS position. PA sidetone will be switched ON
during PASS transmit PTT through Model 700 amplifier control, but only if the Model 700 PA sidetone
input has audio connected to it. Examples of PA amplifiers compatible with the 802-009 PASS key and
volume controls are the NAT Models 205, 240, 250, or 251 Passenger Speaker Amplifiers.
3.3.6.3 Mic Selection
The NORM MIC/OXY MIC rotary switch on the 802-009 selects either the normal boom mic or oxygen
mask mic, depending on its position.
In the NORM MIC position, the NORM mic input is connected to the HOT MIC output and during a
transmit PTT it is connected to the selected transmitter or PA amplifier.
In the OXY MIC position, the OXY mic input is connected to the HOT MIC output and during a transmit
PTT it is connected to the selected transmitter or PA amplifier. In addition, the INPH and SPKR switches
are automatically turned ON, the interphone to speaker function of the Model 700 is initialized and the
interphone volume is set to a preset level determined by the OXY MODE INPH VOL adjustment, which is
accessible through a hole in the rear of the 802-009 enclosure. All selected receiver audio, interphone
audio and transmit sidetone audio will be heard over the cockpit speaker in the OXY MIC mode of
operation. If the OXY MIC MODE INTERCONNECT connection is wired between pilot and copilot
802-009 Switch Panels, then both audio systems will go into this operating mode when either one or the
other selects the OXY MIC position on the NORM MIC/OXY MIC selector switch and only the switch
panel(s) with OXY MIC selected must use the oxygen mask microphone. In either position, the hand mic
with its transmit PTT will override the selected NORM or OXY mic for transmitting only.
Section 3 ends